The credit card application form requires an American Dental Association membership number so I guess you have to be an ADA member to apply. If you are not an ADA member but are interested in the bonus, you may want to consider calling Citibank and asking if they are really care about you having an ADA membership.

Terms:
10,000 bonus Travel Rewards points once you become a cardmember after you make your first purchase with the card within 60 days of account opening.